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GCN Circular 31209

Subject

GRB 211211A: Swift-BAT refined analysis

Date

2021-12-12T03:14:09Z (3 years ago)

From

Amy Lien at GSFC <amy.y.lien@nasa.gov>

M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
A. D'Ai (INAF-IASFPA), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+360 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 211211A (trigger #1088940)
(D'Ai et al., GCN Circ. 31202Loading...
 
 ).  The BAT ground-calculated position is
RA, Dec = 212.272, 27.884 deg which is
   RA(J2000)  =  14h 09m 05.2s
   Dec(J2000) = +27d 53' 03.8"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 21%.

The mask-weighted light curve shows a multi-peaked structure that
starts at ~T0 and ends at ~T+140 s. The main peak occurs at ~T+7 s.
T90 (15-350 keV) is 51.37 +- 0.80 sec (estimated error including
systematics).

The time-averaged spectrum from T0 to T+142.2 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.56 +- 0.02.  The fluence in the 15-150 keV band is 1.5 +- 0.02 x 10^-04
erg/cm2.
The 1-sec peak photon flux measured from T+6.86 sec in the 15-150 keV band
is 155.0 +- 3.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1088940/BA/